Substituted Pyrazole Synthesis for Cost-Effective Industrial Production
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Solution Overview
Problem
Existing methods for the industrial-scale production of pyrazole derivatives, particularly those used to produce pyrazole carboxylic acid precursors for chloranthraniliprole, are limited and lack cost-effectiveness.
Innovation Solution
A method involving the preparation of pyrazole derivatives through reactions such as alkylation, decarboxylation, and oxidation in the presence of specific bases, acids, and solvents, including steps like contacting compounds with brominating agents and oxidants, to produce compounds like 3-bromo-5-methyl-1-H-pyrazole-N-2-chloropyridine, which can be further converted to chloranthraniliprole.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional methods are used for industrial-scale production of pyrazole derivatives, then production capacity is achieved, but cost-effectiveness deteriorates
Solution Approach 1:
The patent changes the chemical parameters of the reaction system by using readily available starting materials (pyridine and brominating agents) and optimizing reaction conditions to achieve high yields of pyrazole carboxylic acid derivatives. This approach maintains industrial production capacity while reducing material costs and improving cost-effectiveness
Solution Approach 2:
The patent employs inexpensive, easily obtainable chemical reagents and simple reaction conditions that can be readily scaled up. The use of common bases, acids, and solvents replaces expensive specialized reagents, thereby reducing manufacturing costs while maintaining productivity
2Quantity of substance
If existing pyrazole preparation methods are used, then pyrazole precursors are produced, but efficiency and cost-effectiveness for industrial scale deteriorates
Solution Approach 1:
The patent divides the synthesis into distinct sequential steps: formation of the pyrazole ring, introduction of the carboxylic acid group, and subsequent derivatization. This segmented approach allows each step to be optimized independently for industrial efficiency while maintaining overall productivity
Solution Approach 2:
The patent performs preliminary formation of the pyrazole core structure before introducing the carboxylic acid functionality. This preliminary action simplifies subsequent steps and improves overall process efficiency for industrial-scale production
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enables efficient, cost-effective industrial-scale production of pyrazole carboxylic acid precursors, enhancing the availability of chloranthraniliprole, a potent anthranilamide insecticide.
Implementation Method 1
contacting of a compound of Formula VI with brominating agent optionally in the presence of base and organic solvent
Implementation Method 2
further decarboxylation of compound of Formula V in the presence of acid
Implementation Method 3
further oxidation of methyl group by potassium permanganate to produce pyrazole carboxylic acids
Data Source
AI summary
A method is disclosed for preparing pyrazole derivative 3-bromo-5-methyl-1-H-pyrazole-N-2-chloropyridine (compound of Formula I) by reacting of a compound of Formula II with halogen substituted pyridine optionally in the presence of base and organic solvent or by decarboxylation of pyrazole carboxylic acid of Formula XI in the presence of acid. In addition, provided a method of preparation of synthetic precursors of Formula II, Formula IV, Formula V, Formula VI, Formula XI, and a method of preparing a compound of Formula VII comprising reacting a compound of Formula I with an oxidant optionally in the presence of a catalyst. Also disclosed a compound of Formula I as useful synthetic precursor for preparation of anthranilamide of Formula VIII.